• 한국식품조리과학회지
• /
• 제30권6호
• /
• pp.695-703
• /
• 2014

Daebong persimmon puree (DPP) prepared from removing the astringency of persimmon was used as a substitute for water when making the dough of white pan bread using domestic wheat flour, and the resulting, quality characteristics were investigated. The moisture content of DPP was 96.69%, and the dough was made by various levels of substitution of DPP for water (0, 10, 30, 50 and 100%). During fermentation, the expansion power of the dough decreased with increasing DPP levels (p<0.05). The volume, specific volume, baking loss, and the L and ${\Delta}E$ values of the crust and crumb of the breads also decreased with increasing DPP levels. The hardness and chewiness of the bread containing 100% DPP (without water) showed the highest values, but the springiness, cohesiveness and resilience showed the opposite trends. In the difference tests, all attributes except air cell uniformity were significantly different (p<0.05). Bread made with 100% substitution of DPP for water achieved the highest scores for flavor, taste and overall acceptability.

• 한국환경과학회지
• /
• 제16권1호
• /
• pp.81-94
• /
• 2007

The purpose of this work is to investigate the water quality change characteristics of treated water in water distribution systems of Water Treatment Plants (WTPs) of Jeju City. For this, the raw water, treated water and tap water that did not pass (named as not pass-tap water) and passed through the water storage tank (named as pass-tap water) were sampled and analyzed monthly from September 2001 to August 2002, for four (W, S, B and O) WTPs except for D WTP (where treated water is not supplied continuously) among WTPs of Jeju City. The concentrations of $NO_3^-$ and $Cl^-$ of treated water in distribution systems changed little, but changed seasonally, which is considered to be based on the seasonal variation of the quality of raw water. The pH of treated water changed little in distribution systems for S WTP, but for the other WTPs, the pH of not pass-tap water was similar to that of treated water and the pH of pass-tap water was higher than that of treated water. The turbidity of treated water in distribution systems changed little except for W2 of W WTP and S4 and S5 of S WTP, where it was higher than that of each treated water. The residual chlorine concentrations between treated water and not pass-tap water changed little, but those between treated water and pass-tap water changed greatly, based on the its long residence time in water storage tank and so its reaction with organic matter, etc or its evaporation. The concentrations of TTHMs (total trihalomethanes) and $CHCl_3$ that induce cancers in water distribution systems of these WTPs, were much lower than their water quality criteria and those in other cities. The concentrations of TTHMs of treated water and not pass-tap water were similar, but concentrations of pass-tap water were 1.5 to 2.0 times higher than those of treated water and not pass-tap water, due to the reaction of residual chlorine and organic matter, etc, with the result of long residence time in water storage tank.

• 환경영향평가
• /
• 제28권3호
• /
• pp.215-230
• /
• 2019

본 연구는 한강 수계의 주요 지류 하천에 통계분석을 이용하여 수질특성을 파악하고 하천 등급화 방법에 따른 우선으로 관리되어야 할 지류 하천을 선정하여 수질 개선 방안을 제시하는 것이다. 한강 수계의 주요 15개 지류 하천을 대상으로 2017년 1월부터 12월까지 유량 및 수질을 모니터링 하였다. 상관 분석 결과 하천 유량은 수질 항목 간의 상관성(p>0.05)이 있지 않았으나 COD와 TOC는 통계적으로 유의한 수준의 높은 상관성을 나타냈다(r=0.957, p<0.01). 주성분 분석 결과 유기오염 물질 및 영양염류에 의한 오염이 수질변동의 주요한 요인으로 나타났으며 BOD, COD, TOC, TN, TP는 일원 분산분석 결과 계절별로 유의한 수준에서 차이가 있는 것으로 나타났다(p<0.05). 정량적 지표에 따른 하천 등급화 결과 수질개선이 필요한 지류 하천은 공공하수처리시설 방류수의 영향을 받는 굴포천, 안양천, 왕숙천, 탄천 등으로 나타났다. 본 연구를 통하여 한강 수계의 수질 개선이 필요한 지류 하천을 선정할 수 있었으며 효율적인 수질 관리를 위한 중요한 자료로 활용될 수 있을 것으로 판단된다.

• Fisheries and Aquatic Sciences
• /
• 제6권3호
• /
• pp.149-154
• /
• 2003

The characteristics of pollutant loads from the various sources and seawater quality in Kwangyang Bay were evaluated. Total flow rate was estimated to be $10,868,066.8 m^3/day$ with a flow rate of R2l (the Seomjin River) as the highest one. Total COD, TN and TP loads of the input rivers and the ditches were about 27,591.8, 25,029.6 and 586.4 kg/day, respectively. Wastewater discharging loads was the greatest contributors to pollutant loads in the inner part of Kwangyang Bay. COD values in the inner part of the bay was over 3.0 mg/L, which exceeded the seawater quality criteria III of Korea. The average values of DIN and DIP were 8.62 ${\mu}gN/L\;and\;1.26\;{\mu}gP/L$, respectively. The limiting factor for algal growth was DIN. In he total discharging loads of the watershed from unit loading estimations, BOD, TN and TP were 9,132.3, 2,727.2 and 304.2 kg/day, respectively. In addition, municipal sewage by the population as pollution sources and the city of Kwangyang as administrative district had the highest loads. For a appropriate water quality recovery of Kwangyang Bay, it is suggested that it is essential to estimate reduction rate of total pollutant loads by water quality modeling.

• 한국물환경학회지
• /
• 제28권6호
• /
• pp.819-832
• /
• 2012

HSPF model based on BASINS was applied for the Hwaseong Reservoir watershed (HRW) to evaluate the feasibility of water quality management. The watershed was divided into 45 sub-basins considering various watershed environment. Streamflow was calibrated based on the measured meteorological data, discharge data of treatment plants and observed streamflow data for 2010 year. Then the model was calibrated against the field measurements of water qualities, including BOD, T-N and T-P. In most cases, there were reasonable agreements between observed and predicted data. The validated model was used to analyze the characterization of pollutant load from study area. As a result, Non-point source pollutant loads during the rainy season was about 66~78% of total loads. In rainy-season, water quality parameters depended on precipitation and pollutant loads patterns, but their concentration were not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. As another result of evaluation for load duration curves, in order to improve water qualities to the satisfactory level, the watershed managements considering both time-variant and pollution sources must be required in the HRW. Overall, it was found that the model could be used conveniently to assess watershed characteristics and pollutant loads in watershed scale.

• 한국물환경학회지
• /
• 제32권3호
• /
• pp.281-290
• /
• 2016

In the northernmost basin of the Bukhan River, pollution sources can have a concentrated distribution. In these basins, small streams show low flow with various and rapid water quality change in low pollutants load. Therefore, a water quality improvement plan of small streams and main stem will be necessary to establish the characteristics of small streams. This study selected a representative Hwacheon-gun in the northernmost basin of the Bukhan River. Hydro analysis was performed with GIS tools using DEM. A total of 152 small streams were listed. A total of 51 survey locations were selected after applying the selection criteria. Flow rate and water qualities were investigated. Pollution sources and pollutants loads were calculated for each basin. Pollution grade and typological classification were performed by cluster analysis using standardized environmental condition factors. As a result, G04, G01, H01 locations were found to have the worst pollution grades whereas J01, P01, and P02 had less pollution. Typological analyses were able to classify six types for the surveyed small streams. An effective water quality improvement plan was obtained based on the results of pollution grade and typological analysis using environmental condition factors of this study.

• 한국환경과학회지
• /
• 제15권5호
• /
• pp.447-459
• /
• 2006

Long-term trends and distribution patterns of water quality were investigated in the Cheonsu Bay of Korea from 1983 to 2004. Water samples were collected at 4 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns were not clear between stations but the seasonal variations were distinctive except COD, SS and nitrate. Twenty two year long-term trend analysis by PCA revealed the significant changes in water quality in the study area. Water quality during 1980's and early 1990's showed high SS, low nutrients and low COD which increased during the mid and late 1990's and early 2000's. Overall water duality in the Cheonsu Bay indicated the increase in nutrients and COD concentration.

• 한국물환경학회지
• /
• 제26권1호
• /
• pp.148-155
• /
• 2010

Water quality and plankton community dynamics after the introduction of two domestic freshwater shellfishes (Unio douglasiae Griffith & Pidgeon and Cipangoplaudina chinese malleata Reeve), were monitored daily in enclosures, which constructed in the tidal zone of eutrophic agricultural reservoir (Shingu reservoir, Korea) for one week between July 31 and August 6, 2007. This biomanipulation study to improve the water quality of eutrophic lake, comprised eight enclosures (duplicate x four kinds), enclosure had no mussels (Control), stocked only with U. douglasiae at density of 60 individuals (UD), stocked only with C. chinese malleata at density of 60 individuals (CCM), and combined-stocked with 30 individuals of UD and 30 individuals of CCM (MIX), respectively. Our results clearly indicate that UD strongly decreased the concentration of chlorophyll-a and increased the water transparency, whereas CCM and MIX (included CCM) did increase algal density or decrease transparency, due perhaps to the disturbance of C. chinese malleata. Therefore, the field application of shellfish to enhance the water quality of eutrophic agricultural reservoir, should consider the grazing characteristics of biological control agents, especially active moving animals like snail.

• 상하수도학회지
• /
• 제25권6호
• /
• pp.839-846
• /
• 2011

To investigate corrosivity characteristics of raw water in Korea, Langelier index (LI) of 30 multi-regional water treatment plants (WTPs) were evaluated. Annual average values of LI at 30 WTPs were all negative, which means raw water in Korea is very corrosive. LI results for 4 major rivers showed that raw water from Han and Nakdong had relatively high values compared to those of Sumjin and Keum. On the other hand, LI values of raw water from the tributaries of four major rivers were relatively low presumably due to geological characteristics, and in some cases the values were less than -4.0 which means increase of LI is urgently needed to minimize red water problem. Based on the correlation results among LI and water quality parameters, pH, water temperature, calcium concentration were confirmed as major components for LI. Therefore, pH and calcium concentration control is an effective method for the improvement of LI in water treatment processes.

• 한국환경과학회지
• /
• 제9권5호
• /
• pp.429-436
• /
• 2000

In order to study on the variational characteristics of water quality and chlorolphyll a concentration the water samples were collected daily or three times a week during the period from April 1990 to November 1991 at Kukdong port located in the northern Kamak bay of Southern Korea I made an analysis on biological factor as chlorophyll a concentration as well as physico-chemical factors such as water temperature salinity sigma-t dissolved oxygen, nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and chemical oxygen demand. In Northern Kamak bay seasonal variations in physical factors such as water temperature salinity and sigma-t were very marked. On the other hand chemical factors such as nutrients concentration and COD were not so. Chemical factors, in particular silicate were influenced by input of freshwater. And the roles of silicate on the seasonal succession of phytoplankton species composition was very low. Phytoplankton biomass as measured by chlorophyll a concentration was very high all the year round and it was controlled by the combination of several factors especially of N/P ratio determined by dissolved inorganic nitrogen.